Laminate membrane, an implant compromising the laminate membrane and a method of manufacturing the same

ABSTRACT

There is provided a laminate membrane for an implant, comprising: an inner layer having an inner layer thickness; a first covering layer disposed on one side of the inner layer, the first covering layer having a first covering layer thickness; and a second covering layer disposed on another side of the inner layer, the second covering layer having a second covering layer thickness.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 16/613,737, filed Nov. 14, 2019, which is a national stageentry of PCT/EP2018/063148, filed May 18, 2018, which claims the benefitof United Kingdom Patent Application No. 1708025.0, filed May 18, 2017,the entireties of which are hereby incorporated by reference.

TECHNICAL FIELD

The present disclosure relates to a laminate membrane, an implantcomprising the laminate membrane and a method of manufacturing the same.More specifically, the present disclosure relates to a laminate membranehaving an inner layer, a first covering layer disposed on one side ofthe inner layer and a second covering layer disposed on another side ofthe inner layer.

BACKGROUND

Embolisation devices for occluding a bodily lumen are disclosed in WO2014/140325 A1 and WO 2016/041961 A2, which are both hereby incorporatedherein by reference.

Such embolisation devices may have a core and a plurality of flexiblebristles which extend radially outwardly from the core. The embolisationdevice may also be provided with a membrane having a contracted deliveryconfiguration and an expanded deployed configuration. The contracteddelivery configuration is such that the embolisation device may beloaded into a delivery catheter allowing the embolisation device to betranslated through the delivery catheter for delivery to a bodily lumen.

However, during translation through a delivery catheter, the membrane ofthe embolisation device may deform, for example, by folding from theinitial contracted delivery configuration due to forces acting on themembrane during translation. Such forces may be exerted by the bristlesof the embolisation device and/or the inner wall of the deliverycatheter.

Furthermore, due to this deformation of the membrane during translationthrough the delivery catheter, expansion of the membrane from thecontracted delivery configuration to the expanded deployed configurationupon delivery to a bodily lumen may not occur in a reliable manner. Insuch cases, the membrane may not expand completely to its intendedexpanded deployed configuration or may exhibit undulations in itssurface. In addition to this, the bristles neighboring the membrane mayalso not expand in a reliable manner upon delivery. For example, thebristles may clump together such that they are not evenly distributedaround the circumference of the device. These issues result in lessocclusion of the bodily lumen, and, due to the uneven distribution ofthe bristles, also result in lower anchoring forces.

Accordingly, there is a need for an improved embolisation device inwhich deformation of the membrane during translation through thedelivery catheter is minimized whilst also allowing reliable expansionof the membrane and adjacent bristles to their expanded deployedconfigurations.

SUMMARY

In a first aspect, there is provided a laminate membrane for an implant,comprising: an inner layer having an inner layer thickness; a firstcovering layer disposed on one side of the inner layer, the firstcovering layer having a first covering layer thickness; and a secondcovering layer disposed on another side of the inner layer, the secondcovering layer having a second covering layer thickness.

In a second aspect, there is provided an implant, comprising: thelaminate membrane of the first aspect, wherein the laminate membrane isconfigured to have a contracted delivery configuration and an expandeddeployed configuration.

In a third aspect, there is provided a method of manufacturing alaminate membrane for an implant, comprising: providing an inner layerhaving an inner layer thickness; providing a first covering layer on oneside of the inner layer, the first covering layer having a firstcovering layer thickness; and providing a second covering layer onanother side of the inner layer, the second covering layer having asecond covering layer thickness.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present disclosure, and to show howthe same may be carried into effect, reference is made, by way ofexample only, to the following exemplary drawings, in which:

FIG. 1 shows a cross-section of a laminate membrane according to oneembodiment of the present disclosure;

FIG. 2 shows a cross-section of a laminate membrane according to anotherembodiment of the present disclosure;

FIG. 3 shows an embolisation device with a laminate membrane accordingto an embodiment of the present disclosure;

FIG. 4 shows the embolisation device shown in FIG. 3 in an expandeddeployed configuration in a bodily lumen;

FIG. 5 shows the embolisation device shown in FIG. 3 in a contracteddelivery configuration within a delivery catheter;

FIG. 6 shows a plan view of a laminate membrane according to embodimentsof the present disclosure; and

FIG. 7 shows a cross-section of a laminate membrane according to anotherembodiment of the present disclosure.

DETAILED DESCRIPTION

FIG. 1 shows a cross-section of a laminate membrane 10 according to anembodiment of the present disclosure. The laminate membrane 10 comprisesan inner layer 11 having an inner layer thickness X, a first coveringlayer 12 having a first covering layer thickness Y and a second coveringlayer 13 having a second covering layer thickness Z. The first coveringlayer 12 is disposed on one side of the inner layer 11. The secondcovering layer 13 is disposed on another side of the inner layer 11. Inthis embodiment, the first covering layer 12 is disposed on one side ofthe inner layer 11, and the second covering layer 13 is disposed on theopposite side of the inner layer 11.

As shown in FIG. 6 , laminate membrane 10 and each of the inner layer11, first covering layer 12 and second covering layer 13 may bedisc-shaped. The laminate membrane 10 may have a central through-hole H.

First covering layer 12 may entirely cover one side of the inner layer11. Second covering layer 13 may entirely cover the other side of theinner layer 12.

The laminate membrane 10 may be configured to have a contracted deliveryconfiguration and an expanded deployed configuration. In the contracteddelivery configuration (see FIG. 5 ), the laminate membrane 10 forms aconical shape with a smaller radial extent than in the expanded deployedconfiguration (see FIG. 4 ).

The inner layer 11 provides the backbone of the laminate membrane 10which provides structural properties of the laminate membrane 10 such asstiffness and elasticity. In this embodiment, the first covering layer12 and the second covering layer 13 are outermost surface layers of thelaminate membrane 10. The first covering layer 12 and the secondcovering layer 13 dictate the properties of the outer surface of thelaminate membrane 10 such as the frictional properties and surfaceenergy.

The first covering layer 12 and the second covering layer 13 may each bemade from a lower friction material than the material from which theinner layer 11 is made.

The skilled person will be aware of many different ways of determiningwhether a material is a lower friction material than another material.For example, the materials to be compared may be formed so as to haveflat surfaces, and the surface energy, surface roughness, or staticcoefficient of friction (relative to itself or another common surface)of these surfaces may be measured, as would be understood by the skilledperson. The flat surfaces of each of the materials being tested may beformed by the same process (e.g. each formed by electrospinning,extrusion, film casting, dip casting, spin casting, spray deposition orvapor deposition).

In other words, at least one of the first covering layer 12 and thesecond covering layer 13 are made of a material which exhibit a lowersurface roughness or static coefficient of friction (measured relativeto itself or another common surface) than the material from which theinner layer 11 is made of.

The stiffness of the inner layer 11 may be greater than the stiffness ofeach of the first covering layer 12 and the second covering layer 13.

The elasticity of the first covering layer 12 and/or the second coveringlayer 13 may be higher than or equal to the elasticity of the innerlayer 11. In such cases, the laminate membrane 10 may allow for acontracted delivery configuration with a lower radial profile withoutrisk of permanent deformation as the first covering layer 12 and/or thesecond covering layer 13, which experience greater elongation duringbending of the laminate membrane 10 than the inner layer 11, are betterable to stretch relative to the inner layer 11.

Various materials may be used for the inner layer 11, first coveringlayer 12 and the second covering layer 13.

For example, the inner layer 11 may consist of polyurethane (PU) andeach of the first covering layer 12 and the second covering layer 13 mayconsist of polytetrafluoroethylene (PTFE). In this case, the inner layer11 of PU provides high stiffness to the laminate membrane 10, whereasthe first covering layer 12 and the second covering layer 13 of PTFEresult in the outer surface of the laminate membrane 10 having lowfriction. The high stiffness may allow the laminate membrane 10 toreliably transition from the contracted delivery configuration to theexpanded deployed configuration, whilst the low friction surfaces mayreduce deformation during translation.

In this embodiment, first covering layer thickness Y and second coveringlayer thickness Z are the same, and the first covering layer thickness Yand the second covering layer thickness Z are each smaller than theinner layer thickness X.

The inner layer thickness X may be between 4 to 8 μm, and the firstcovering layer thickness Y and the second covering layer thickness Z maybe between 1 to 3 μm. In another embodiment, the inner layer thickness Xmay be between 6 to 10 μm, and the first covering layer thickness Y andthe second covering layer thickness Z may be between 1 to 4 μm.

The laminate membrane 10 may be manufactured by providing the innerlayer 11, providing the first covering layer 12 on one side of the innerlayer 11, and providing a second covering layer 13 on another side ofthe inner layer 11. Each of the inner layer 11, first covering layer 12and the second covering layer 13 may be deposited using electrospinning.

FIG. 2 shows a cross-section of a laminate membrane 20 according toanother embodiment comprising an inner layer 21 having an inner layerthickness X′, a first covering layer 22 having a first covering layerthickness Y′ and a second covering layer 23 having a second coveringlayer thickness Z′. The first covering layer 22 is disposed on one sideof the inner layer 21. The second covering layer 23 is disposed on theopposite side of the inner layer 21.

The inner layer thickness X′ may be between 4 to 8 μm, and the firstcovering layer thickness Y′ and the second covering layer thickness Z′may be between 1 to 3 μm. In another embodiment, the inner layerthickness X′ may be between 6 to 10 μm, and the first covering layerthickness Y′ and the second covering layer thickness Z′ may be between 1to 4 μm.

Laminate membrane 20 is similar to laminate membrane 10 shown in FIG. 1, except that first covering layer 22 and second covering layer 23 alsocover the outer edge surface of the inner layer 11. In particular, firstcovering layer 22 and second covering layer 23 also cover the curvededge surface of the inner layer 11. Hence, the first covering layer 22and the second covering layer 23 together cover all external surfaces ofthe inner layer 21.

FIG. 3 shows an embolisation device 30 according to an embodiment of thepresent disclosure. The embolisation device 30 has a longitudinallyextending core 31 and a plurality of flexible bristles 32 extendingoutwardly from the core, the flexible bristles 32 are configured to havea contracted delivery configuration and an expanded deployedconfiguration in which the flexible bristles 32 extend generallyradially outwardly from the core to anchor the device in a bodily lumen.The flexible bristles 32 may be configured to be resilient such thatthey are biased from their contracted delivery configuration to theirexpanded deployed configuration.

The embolisation device 30 also has a laminate membrane 33 disposed onthe core 31. The laminate membrane 33 may be any of the laminatemembranes described herein. The laminate membrane 31 may have athrough-hole which allows the core 31 to pass through the laminatemembrane 31. The laminate membrane 33 is configured to occlude flowthrough the bodily lumen.

The laminate membrane 30 is positioned on the core 31 within a segmentof flexible bristles 32. Some flexible bristles 32 a are disposedproximally adjacent to one side of the laminate membrane 33 and someflexible bristles 32 b are disposed distally adjacent to the oppositeside of the laminate membrane 33.

FIG. 4 shows the embolization device 30 in its expanded deployedconfiguration in a bodily lumen 40, where the flexible bristles 32 andthe laminate membrane 33 are in their expanded deployed configurations.In this configuration, the laminate membrane 33 occludes flow throughthe bodily lumen 40. The flexible bristles 33 anchor the embolisationdevice 30 in the bodily lumen 40, preventing migration of theembolisation device 30.

The orientation of the expanded laminate membrane 33 in its expandeddeployed configuration and the orientation of the expanded flexiblebristles 32 in the expanded deployed configuration is the same. Forexample, both the laminate membrane 33 and the adjacent flexiblebristles 32 may be deployed pointing distally or proximally.

FIG. 5 shows the embolization device 30 in its contracted deliveryconfiguration in a delivery catheter 50, where the flexible bristles 32and the laminate membrane 33 are in their contracted deliveryconfigurations. When the flexible bristles 32 and the laminate membrane33 are in their contracted delivery configurations, at least a portionof the laminate membrane 31 contacts the delivery catheter. In thecontracted delivery configuration, the embolisation device 30 may betranslated through the delivery catheter 50.

The orientation of the collapsed laminate membrane 33 in its contracteddelivery configuration and the orientation of the collapsed flexiblebristles 32 in the contracted delivery configuration is the same. Forexample, both the laminate membrane 33 and the adjacent flexiblebristles 32 may be collapsed pointing distally or proximally.

Using any of the laminate membranes as described herein may provide anembolisation device 30 in which deformation of the membrane 33 duringtranslation through the delivery catheter 50 is minimized whilst alsoallowing reliable expansion of the membrane 33 and adjacent bristles 32to their expanded deployed configurations.

Although the above explanation is considered to fully clarify how thepresent disclosure may be straight-forwardly put into effect by thoseskilled in the art, it is to be regarded as purely exemplary. Inparticular, there are a number of variations which are possible, as maybe appreciated by those skilled in the art.

For example, even though the above laminate membranes are disc-shaped,they may be of any shape such as rectangular, square or cylindrical.

Further, even though the above laminate membranes are described inrelation to an embolisation device with a core and a plurality offlexible bristles, laminates according to the present disclosure arealso applicable to any type of embolisation device.

Specifically, according to an aspect of the present disclosure, there isprovided an embolisation device, comprising: a laminate membrane asdescribed herein.

In an embodiment, the laminate membrane is configured to have acontracted delivery configuration and an expanded deployedconfiguration. The embolisation device may comprise an embolisationcoil. The laminate membrane may be disposed around at least part of theembolisation coil. At least a part of the laminate membrane may bedisposed between adjacent turns in the embolisation coil.

Furthermore, even though the above laminate membranes are described inrelation to embolisation devices, laminate membranes according to thepresent disclosure are also applicable to any type of medical implant,and, in particular, a medical implant with a contracted deliveryconfiguration and an expanded deployed configuration, where the medicalimplant is configured to be delivered to a bodily lumen in thecontracted delivery configuration. For example, the laminate membranesaccording to the present disclosure are particularly suited toexpandable stents. Using the laminate membranes of the presentdisclosure may reduce deformation of the membrane during translationthrough the delivery catheter whilst also allowing reliable expansion ofthe membrane to its expanded deployed configuration.

Further, each of the inner layer, first covering layer and the secondcovering layer may be made from various materials. For example, theinner layer may be made from a composite of polyurethane and one or moreother materials. In particular, the inner layer may be made from apolyurethane and polytetrafluoroethylene composite or a copolymer of 90%55D polyurethane and 10% silicone, by weight. In other embodiments, theinner layer 11 may comprise, or consist of, condensed PTFE orfluorinated ethylene propylene (FEP).

Each of the first covering layer and the second covering layer may bemade from a composite of materials. The first covering layer and thesecond covering layer may be made from different materials from eachother. First covering layer may be made from: a hydrophobic materialsuch as polytetrafluoroethylene and/or ultra-high molecular weightpolyethylene; a hydrophilic material; and/or silicone. The secondcovering layer may be made from: a hydrophobic material such aspolytetrafluoroethylene and/or ultra-high molecular weight polyethylene;a hydrophilic material; and/or silicone.

Further, the structural properties of the inner layer, first coveringlayer and the second covering layer may be varied from the above. Inparticular, the inner layer may have higher elastic recovery,tear-resistance and/or permeability than at least one of the firstcovering layer and the second covering layer. At least one of the firstcovering layer and the second covering layer may have lower surfaceenergy than the inner layer.

In the above embodiments, the inner layer, the first covering layer andthe second covering layer are each single layers. However, inalternative embodiments, the inner layer, the first covering layerand/or the second covering layer may each be formed of multiplesub-layers.

Further, the above laminate membranes may further comprise a tie-layerdisposed between the inner layer and one or each of the first coveringlayer and the second covering layer. Such a tie-layer may increase theadherence between the layers. As an example, such a tie-layer may beDuPont™ Bynel®. The tie-layers may be made from: modified ethylene vinylacetate polymer; acid modified ethylene acrylate resin; anhydridemodified ethylene acrylate resin; or anhydride-modified linearlow-density polyethylene resin. Generally, the tie-layers may be madefrom ethylenes including acetates & acrylates thereof. FIG. 7 shows anexemplary embodiment of a laminate membrane 60 comprising tie-layers 64,65. The laminate membrane 60 is similar to laminate membrane 10 in thatin has an inner layer 61, first covering layer 62 and second coveringlayer 63. However, laminate membrane 60 has a first tie-layer 64disposed between the inner layer 61 and the first covering layer 62, anda second tie-layer 65 disposed between the inner layer 61 and the secondcovering layer 63.

In some embodiments, the inner layer and the first covering layer and/orthe second covering layer may be chemically or electrostatically adheredto each other.

Furthermore, even though the above manufacturing method uses anelectrospinning process for forming each of the layers, various othermanufacturing methods may be used. For example, the layers may be formedby electrospinning, extrusion, film casting, dip casting, spin casting,spray deposition or vapor deposition. Furthermore, different layers maybe formed by different methods. For example, the inner layer may beformed from dip casting or spray casting. The first covering layer andthe second covering layer may each be formed by electrospinning onto theinner layer.

All of the above are fully within the scope of the present disclosure,and are considered to form the basis for alternative embodiments inwhich one or more combinations of the above described features areapplied, without limitation to the specific combinations disclosedabove.

In light of this, there will be many alternatives which implement theteaching of the present disclosure. It is expected that one skilled inthe art will be able to modify and adapt the above disclosure to suitits own circumstances and requirements within the scope of the presentdisclosure, while retaining some or all technical effects of the same,either disclosed or derivable from the above, in light of his commongeneral knowledge in this art. All such equivalents, modifications oradaptions fall within the scope of the present disclosure.

What is claimed is:
 1. An embolisation device comprising: a core; aplurality of flexible bristles extending outwardly from the core, theflexible bristles having a contracted delivery configuration and anexpanded deployed configuration in which the flexible bristles extendradially outwardly from the core; and a laminate membrane mounted to thecore, wherein the laminate membrane comprises: an inner layer having aninner layer thickness; a first covering layer disposed on one side ofthe inner layer, the first covering layer having a first covering layerthickness; and a second covering layer disposed on another side of theinner layer, the second covering layer having a second covering layerthickness, wherein the laminate membrane is configured to have acontracted delivery configuration and an expanded deployed configurationconfigured to diametrically occlude flow through a bodily lumen and forman embolisation, and wherein the stiffness of the inner layer is greaterthan the stiffness of at least one of the first covering layer and thesecond covering layer.
 2. The embolisation device of claim 1, whereinthe embolisation device is configured to be delivered to the bodilylumen by a delivery catheter when the laminate membrane is in thecontracted delivery configuration, and wherein in the contracteddelivery configuration at least a portion of the laminate membrane isconfigured to abut an inner wall of the delivery catheter.
 3. Theembolisation device of claim 1, wherein the laminate membrane isdisposed adjacent to at least some of the flexible bristles.
 4. Theembolisation device of claim 3, wherein at least some of the flexiblebristles are disposed on either side of the laminate membrane.
 5. Theembolisation device of claim 1, wherein the surface energy, surfaceroughness, or static coefficient of friction of the at least some of theplurality of flexible bristles is less than the laminate membrane.